How to use the write() function to write content to a file in Python 3.x

How to use the write() function to write content to a file in Python 3.x

In Python programming, sometimes we need to write data to a file for later use or sharing with others. The write() function in Python is used to implement this function. This article will introduce how to use the write() function to write content to a file in Python 3.x.

The write() function is a built-in function in Python, which is used to write content to an open file object. Before using the write() function, we need to use the open() function to open the file and obtain a file object. Below is a simple example that demonstrates how to write to a file using the write() function.

# 打开文件
file = open('example.txt', 'w')

# 写入内容
file.write('这是一个示例文件，用于演示write()函数的使用。
')
file.write('这是第二行内容。
')

# 关闭文件
file.close()

In the above example, we first used the open() function to open a file named example.txt, and specified the mode as 'w', which means opening the file in write mode. Next, we use the write() function to write content to the file. In this example, we have written two lines of text. Each time the write() function is called, it appends the contents to the end of the file. Finally, we use the close() function to close the file.

It is worth noting that when using the write() function to write content, we need to pass the content to it as a parameter. In the example, we pass the content as a string to the write() function. If you need to write other types of data, you can use the str() function to convert it to a string.

In addition to ordinary text content, the write() function can also write binary data. For example, we can write image or audio data to a file. When writing binary data to a file, the file needs to be opened in binary mode. Below is an example showing how to write binary data.

# 打开文件
file = open('example.jpg', 'wb')

# 写入二进制数据
data = b'
    '
file.write(data)

# 关闭文件
file.close()

In the above example, we opened a file named example.jpg and specified the mode as 'wb', which means opening the file in binary writing mode. Then, we define a bytes object containing binary data and pass it as a parameter to the write() function.

It should be noted that before using the write() function to write content, try to ensure that the file object has been opened correctly and is writable. Otherwise, the write() function will throw an exception. Additionally, if the file already exists and is opened in write mode, the write() function will overwrite the original file contents. If you want to append new content to the original content, you can open the file in 'a' mode.

Summary:

This article introduces how to use the write() function to write content to a file in Python 3.x. We use the open() function to open the file and obtain a file object. Then, we call the write() function to write content to the file. Finally, we close the file using the close() function. It should be noted that the write() function can write text and binary content. When writing binary data, the file needs to be opened in binary mode.

By mastering the use of the write() function, we can easily write data to files and implement more functions, such as data persistence, data backup, etc. In actual development, we can use the write() function reasonably and flexibly according to specific needs to meet our needs.

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